Tested: KW Suspensions BMW F30 DDC Remote Adjustable Suspension
A few years ago we got to test a sample of KW Suspensions' electronically adjustable DDC coilovers while visiting them at their German global headquarters. We sampled a 3 series BMW coupe on twisty German back roads and on the Autobahn and came away favorably impressed. We were able to easily, and quickly, adjust the suspension from comfortable to firm to match our current driving modd and/or road conditions.
We were eager to test the KW DDC suspension to see how it would do with a US spec car on US spec roads. We obtained a set of production KW DDC coilovers and a bone stock F30 BMW sedan to perform our own evaluation on our home turf.
The DDC dampers look almost like your typical KW Variant III coilovers. The differences are that there is a solenoid valve sticking out of the side of the shock body and the shock bodies are slightly fatter than a V3 or Clubsport.The DDC is actually a triple tube damper. The deep insides are like a conventional twin tube with an inner tube which the piston and rod ride in. Fluid flows through the piston and also through the foot valve on the bottom of the inner tube into the second tube.
Most of the rebound damping is controlled by the piston and the compresison damping is handled by the foot valve. However, a large amount of fluid that is displaced by the shock shaft as the shaft moves up and down still flows through the second tube to the outer third tube.
The solenoid valve controls the fluid flow between the second and third tubes. The solenoid valve action is computer controlled and the control can change the damping forces by metering the fluid flow.
The KW DDC uses the same Inox stainless steel in the body of the shock for corrosion resistance just like the V3 and Clubsport. It also uses the same non-rusting plastic, steel reinforced spring perch. Like all street KW's this shock is very rust resistant and carries KW's limited lifetime warranty. The DDC shock body has OEM like mounts for the brake lines and ABS sensors. The shock also has dust covers and soft, progressive MCU bumpstops.
The DDC shock uses OEM style weather resistant plugs. For some cars that have OE adaptive suspension systems like Audis, BMWs and VWs the DDC is plug and play, compatible with the OEM driver adjustable controls. They also make systems that will allow you to easily add an adapative suspension system even if your car did not come with one from the factory. Such is the case for the BMW test mule. Our KW DDC system comes with its own shock controller, wire harness and DDC activation controls.
In our F30 BMW the rear coil springs are divorced from the shock bodies and sit inboard on the rear lower control arms. KW supplies these cool threaded spring seats so that ride height and corner balance can be adjusted. The spring seats are hard anodized aluminum for corrosion resistance.
This is the control unit for the KW DDC shocks. It commands the solenoid valves to control the ride characteristics of the shock itself. 
